Effects of propidium monoazide (PMA) treatment on mycobiome and bacteriome analysis of cystic fibrosis airways during exacerbation

Introduction and Purpose : Propidium monoazide (PMA)-pretreatment has increasingly been applied to remove the bias from dead or damaged cell artefacts, which could impact the microbiota analysis by high-throughput sequencing. Our study aimed to determine whether a PMA-pretreatment coupled with high-throughput sequencing analysis provides a different picture of the airway mycobiome and bacteriome. Results and Discussion : We compared deep-sequencing data of mycobiota and microbiota of 15 sputum samples from 5 cystic fibrosis (CF) patients with and without prior PMA-treatment of the DNA-extracts. PMA-pretreatment had no significant effect on the entire and abundant bacterial community (genera expressed as operational taxonomic units (OTUs) with a relative abundance greater than or equal to 1%), but caused a significant difference in the intermediate community (less than 1%) when analyzing the alpha biodiversity Simpson index (p = 0.03). Regarding PMA impact on the airway mycobiota evaluated for the first time here; no significant differences in alpha diversity indexes between PMA-treated and untreated samples were observed. Regarding beta diversity analysis, the intermediate communities also differed more dramatically than the total and abundant ones when studying both mycobiome and bacteriome. Our results showed that only the intermediate (or low abundance) population diversity is impacted by PMA-treatment, and therefore that abundant taxa are mostly viable during acute exacerbation in CF. Given such a cumbersome protocol (PMA-pretreatment coupled with high-throughput sequencing), we discuss its potential interest within the follow-up of CF patients. Further studies using PMA-pretreatment are warranted to improve our "omic" knowledge of the CF airways

MICRA: an automatic pipeline for fast characterization of microbial genomes from high-throughput sequencing data

Abstract The increase in available sequence data has advanced the field of microbiology; however, making sense of these data without bioinformatics skills is still problematic. We describe MICRA, an automatic pipeline, available as a web interface, for microbial identification and characterization through reads analysis. MICRA uses iterative mapping against reference genomes to identify genes and variations. Additional modules allow prediction of antibiotic susceptibility and resistance and comparing the results of several samples. MICRA is fast, producing few false-positive annotations and variant calls compared to current methods, making it a tool of great interest for fully exploiting sequencing data

Additional file 1: of MICRA: an automatic pipeline for fast characterization of microbial genomes from high-throughput sequencing data

Supplementary figures, notes, and tables. (PDF 3297 kb

Photodynamic therapy relieves colitis and prevents colitis-associated carcinogenesis in mice

International audienceABSTRACT Background: Inflammatory bowel diseases (IBD) are incurable illnesses of the gastrointestinal tract which substantially enhance the risk of developing colorectal carcinogenesis. Conventional photodynamic therapy (PDT) is a clinically approved therapeutic modality used in the treatment of neoplastic diseases. Recent preclinical and clinical studies have shown that PDT with low doses of photosensitizer and/or light improves inflammatory conditions, including colitis. The present study aims therefore at investigating the therapeutic potential of low-dose photodynamic therapy (LDPDT) with a liposomal formulation of meta-tetra(hydroxyphenyl)chlorin (namely Foslip®) in the prevention of colitis-associated cancer in mice. Methods: LDPDT efficacy was evaluated by endoscopic, macroscopic, and histological analysis. MPO levels were quantified by ELISA and cytokines expression by quantitative RT-PCR analysis. The integrity of the intestinal barrier was evaluated by immunostaining and bacterial composition of the faecal microbiota was determined by 454 pyrosequencing of V3-V4 region of bacterial 16S rRNA genes.Results: LDPDT reduced intestinal tumor growth by decreasing the expression of a wide range of inflammatory mediators and by lowering neutrophil influx. LDPDT treatment prevents onset of a dysbiotic microbiota in the colitis-associated cancer model.Conclusion: LDPDT with Foslip® could be considered as a novel treatment modality to prevent colorectal carcinogenesis in IBD patients

Abundance and α-diversity comparison of bacteriome and mycobiome between PMA-pretreated and untreated samples.

<p>Abundance and α-diversity comparison of bacteriome and mycobiome between PMA-pretreated and untreated samples.</p

Effect of PMA on the composition of mycobiome of each sample.

<p><b>(A)</b>: Relative abundance of fungal genera of each sample (“yes” or “no” indicates the samples with or without PMA-pretreatment). <b>(B)</b>: PCA plot of the first two components of mycobiome of samples with and without PMA-pretreatment. Each marker represents treatment conditions (filled triangle symbols PMA-treated samples, filled square symbols untreated samples). Each color represents a given sputum sample (G040.III: dark blue; G088.II: chartreuse; G088.III: dark green; G172.I: yellow; G172.II: orange; G172.III: dark orange; G014.II: dark grey; G014.III: black; G176.II: firebrick; G176.III: dark red).</p

Venn diagram representing number of shared and specific bacterial (A) and fungal (B) genera between PMA-treated and untreated samples.

<p>In each case, the first 5 most prevalent genera are listed.</p

<i>p-values</i> and <i>r-values</i> of similarity analysis (one-way ANOSIM) of the bacterial and fungal OTU data.

<p><i>p-values</i> and <i>r-values</i> of similarity analysis (one-way ANOSIM) of the bacterial and fungal OTU data.</p